U.S. patent application number 10/594958 was filed with the patent office on 2008-10-30 for device for indicating fuel filter clogging in internal combustion engines, particularly diesel engines.
This patent application is currently assigned to UFI FILTERS S.P.A.. Invention is credited to Giorgio Girondi.
Application Number | 20080264153 10/594958 |
Document ID | / |
Family ID | 34961743 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080264153 |
Kind Code |
A1 |
Girondi; Giorgio |
October 30, 2008 |
Device for Indicating Fuel Filter Clogging in Internal Combustion
Engines, Particularly Diesel Engines
Abstract
A device for indicating clogging of the fuel filter (1) of
internal combustion engines, in particular diesel engines, the
filter comprising an outer casing (2) closed by a cover (3) of
amagnetic material, and a filter element (5) which, together with
the disc (30) to which it is connected, defines two chambers (6 and
7) for fuel entry and exit respectively; said device comprises a
pressure sensor means (10) sensing the difference between the entry
and exit fuel pressure and housed inside the filter casing, and a
means (20) for generating a signal proportional to said pressure
difference which is located outside the filter casing and is not
mechanically connected to the pressure sensor means.
Inventors: |
Girondi; Giorgio; (Mantova,
IT) |
Correspondence
Address: |
BROWDY AND NEIMARK, P.L.L.C.;624 NINTH STREET, NW
SUITE 300
WASHINGTON
DC
20001-5303
US
|
Assignee: |
UFI FILTERS S.P.A.
MANTOVA
IT
|
Family ID: |
34961743 |
Appl. No.: |
10/594958 |
Filed: |
March 23, 2005 |
PCT Filed: |
March 23, 2005 |
PCT NO: |
PCT/EP2005/003249 |
371 Date: |
September 29, 2006 |
Current U.S.
Class: |
73/114.31 |
Current CPC
Class: |
B01D 35/143 20130101;
F02M 37/40 20190101; B01D 29/232 20130101; B01D 29/606
20130101 |
Class at
Publication: |
73/114.31 |
International
Class: |
G01M 15/00 20060101
G01M015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2004 |
IT |
RE2004A000032 |
Claims
1. A device for indicating clogging of the fuel filter of internal
combustion engines, in particular diesel engines, the filter
comprising an outer casing closed by a cover of amagnetic material,
and a filter element which, together with the disc to which it is
connected, defines two chambers for fuel entry and exit
respectively, characterised by comprising a pressure sensor means
sensing the difference between the entry and exit fuel pressure and
housed inside the filter casing, and a means for generating a
signal proportional to said pressure difference which is not
mechanically connected to the pressure sensor means and is located
outside the filter casing.
2. An indicator device as claimed in claim 1, characterised in that
the pressure sensor means comprises: an elastically deformable
element which defines a variable volume inside the fuel entry or
exit chamber; a conduit which connects said volume to the other
chamber; and a magnet which, associated with the flexible element,
moves to follow its elongation or contraction.
3. An indicator device as claimed in claim 2, characterised in that
said pressure sensor means is housed in the fuel entry chamber.
4. An indicator device as claimed in claim 2, characterised in that
said elastically deformable element is fixed, by known means, to
the filter cartridge connection disc.
5. An indicator device as claimed in claim 2, characterised in that
said flexible element is a bellows.
6. An indicator device as claimed in claim 2, characterised in that
said flexible element is a membrane.
7. An indicator device as claimed in claim 2, characterised in that
said conduit is a through hole passing through the thickness of the
filter cartridge connection disc, in correspondence with the
flexible element.
8. An indicator device as claimed in claim 2, characterised in that
said signal generating means comprise: a Hall sensor sensitive to
the magnetic field of the magnet of the pressure sensor means, and
a processor for processing the voltage signal generated by the Hall
sensor.
9. An indicator device as claimed in claim 7, characterised in that
the signal generating means is positioned on the filter cover.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a fuel filter for
use in internal combustion engines, and more particularly in diesel
engines.
PRIOR ART
[0002] Diesel fuel normally contains impurities, or more or less
solid substances (especially paraffins) which separate at
relatively low temperature.
[0003] For this reason the engine feed system must be provided with
a suitable filter able to clean the fuel.
[0004] Modern diesel fuel filters generally consist of a cup-shaped
outer casing and a closure cover. Said casing contains a coaxial
filter cartridge of toroidal form which, when fixed to a connection
disc, separates the internal volume of the cup into an entry
chamber and an exit chamber for the fuel.
[0005] In retaining said impurities, said cartridge progressively
clogs and has therefore to be periodically replaced.
[0006] However, said clogging does not always take place gradually,
hence the clogging time is not constant and cannot be taken as a
parameter for the regular replacement of the cartridge.
[0007] To determine the replacement interval such as to prevent the
appearance of dangerous external particulate inclusions in the
fuel, automatic diagnostic devices are known.
[0008] Based on the observation that the fuel pressure difference
between the filter inlet and outlet is a quantity related, to a
sufficiently reliable and significant extent, to the degree of
clogging of the filter, said devices activate indicator means when
a limiting value of said pressure difference is exceeded.
[0009] Said devices generally comprise a cylindrical chamber and a
piston slidable in its interior to divide it into two
half-chambers, of which one communicates with the fuel inlet and
the other with the fuel outlet. Said chamber, which can be provided
directly within the filter casing or within a separate container,
also houses a spring means acting on the piston against the action
of the pressure difference, and an electromechanical or
electromagnetic switch providing a signal as the result of a
movement of said piston against the action of the spring.
[0010] The described device is mounted in suitable seats provided
in the filter casing and fixed thereto by known means by way of
suitable seal gaskets. However this configuration presents certain
drawbacks: firstly, problems in sealing the filter against the
external environment inevitably arise at the fixing between the
seat and the device; in addition, the provision of said seats
considerably complicates construction, while the presence of the
gaskets makes it more difficult to mount and replace the device.
Finally, these factors also produce a cost increase that cannot be
ignored.
DISCLOSURE OF THE INVENTION
[0011] The object of the present invention is to overcome the
stated drawbacks within the context of a simple, rational and
low-cost solution.
[0012] The invention attains said object by virtue of the
characteristics indicated in the claims.
[0013] In particular, the invention provides a device for
indicating clogging of the fuel filter of internal combustion
engines, comprising a pressure sensor means sensing the difference
between the entry and exit fuel pressure and housed within the
filter casing, and a means for generating a signal proportional to
said pressure difference which is located outside the filter casing
and is not mechanically connected to the pressure sensor means. By
virtue of this solution, a device according to the invention does
not induce sealing problems, is of simple installation and
replacement, and is of low cost.
[0014] According to the preferred embodiment, the pressure sensor
means comprises an elastically deformable element, for example a
membrane or a bellows, mounted within the fuel entry chamber. When
associated with the filter cartridge connection disc, said
elastically deformable element defines a volume which communicates
with the fuel exit chamber via a hole passing through the body of
the disc. A magnet, associated with said elastically deformable
element, is positioned such as to be able to move as a result of
deformation of the sensor means.
[0015] Externally, the signal generating means is fixed, by a screw
fixing, by insertion or by gluing, to the filter cover in a
position corresponding with the underlying pressure sensor
means.
[0016] According to the invention, said signal generating means
comprises a Hall sensor, which emits a voltage signal proportional
to the proximity of the magnet, and hence to the pressure
difference, and a processor able to process it.
[0017] By this solution, the invention handles an analogue signal,
hence allowing continuous monitoring of the state of the filter,
and does not merely indicate when clogging has taken place, as in
the case of known devices. Moreover, when necessary, the acceptable
limiting value of the pressure difference can be easily and quickly
adjusted by acting merely on the electronic parameters of the
device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The characteristics and the constructional merits of the
invention will be more apparent from the ensuing description given
with reference to the figures of the accompanying drawings which
illustrate a particular preferred embodiment by way of non-limiting
example.
[0019] FIG. 1 is a side section through a filter of the
invention;
[0020] FIG. 2 shows on an enlarged scale the detail III of FIG. 1,
in the configuration with a new filter cartridge
[0021] FIG. 3 shows the same detail as FIG. 2, but in the
configuration with the cartridge clogged.
BEST MODE FOR CARRYING OUT THE INVENTION
[0022] Said figures, and in particular FIG. 1, show a diesel fuel
filter for installation on a diesel engine.
[0023] Said filter, indicated by the reference numeral 1, comprises
a cup-shaped outer casing 2, and an upper cover 3 of amagnetic
material sealedly fixed to the casing by a ring nut 4.
[0024] Inside the casing 2 a disc 30 supports a filter cartridge 5
which divides the inner volume of the filter into two chambers, one
6 for the diesel fuel to be filtered, and the other 7 for the
filtered diesel fuel, they being associated with an inlet conduit
and an outlet conduit respectively.
[0025] In the chamber 6 (see FIGS. 2 and 3) there is inserted a
pressure sensor means 10, composed of an extendable membrane 11, a
hole 12 which connects the volume on the inside of the membrane to
the filtered diesel oil chamber 7, and a magnet 13 mounted on said
membrane 11. The pressure sensor 10 is configured such that
elongation or contraction of the membrane 11, and with it an axial
movement of the magnet 13, takes place in response to variation in
the pressure difference between the filtered diesel oil chamber 7
and the chamber 6 for the diesel oil to be filtered.
[0026] On the cover 3, in proximity to the sensor means 10, a
signal generating means 20 is mounted, comprising a Hall sensor 21,
a processor 22 and an output cable 23.
[0027] During normal operation of the diesel oil filter 1, with the
cartridge 5 unclogged (see FIG. 2), the pressure in the chamber 6
upstream of the filter is virtually equal to the pressure in the
downstream chamber 7.
[0028] In this state the membrane 11 is at its maximum elongation
allowed by its shape, and the magnet 13 at the minimum distance
from the Hall sensor 21 which hence indicates high magnetic field
intensity. Said intensity, converted by the sensor 21 into a
proportional voltage signal, is recognized by the processor 22 as
indicative of a clean filter.
[0029] When the cartridge 5 begins to clog, the pressure in the
chamber 6 containing diesel oil to be filtered increases relative
to the pressure in the filtered diesel oil chamber 7. The pressure
difference, opposed only by the rigidity of the membrane 11, causes
it to lower with corresponding withdrawal of the magnet 13 from the
Hall sensor 21.
[0030] As the distance varies, the intensity of the sensed magnetic
field varies, as does the intensity of the voltage signal emitted
by the Hall sensor.
[0031] An analogue quantity is therefore available which the
processor is able to evaluate at each moment in the life of the
filter, and when this falls below a value corresponding to
excessive clogging of the cartridge 1 it indicates the need for its
replacement.
* * * * *